The present invention relates to a development apparatus applied to copying machines, printers, facsimiles and complex machines having these multiple functions, in which images are reproduced with use of, for example, powder developers, and further relates to a process cartridge having the development apparatus and an image formation apparatus having the development apparatus.
Conventionally, in the field of electrophotographic image formation apparatuses for reproducing images with use of powder developers, various technologies have been proposed for the purpose of preventing the powder developers from flying away from development apparatuses which feed powder developers to electrostatic latent images formed on electrostatic latent image holder and develop the images.
For example, there has been disclosed a technology where a smoky dust prevention sheet is stuck on a regulation plate for regulating an amount of a developer transported by a development roller, and one end of the smoky dust prevention sheet is brought into contact with the development roller in order to seal a gap between the development roller and the regulation plate with the smoky dust prevention sheet (see JP 2000-284590 A).
However, in the conventional development apparatus, the smoky dust prevention sheet is simply stuck on the regulation plate, and a sticking area of the smoky dust prevention sheet is extremely small. Therefore, the smoky dust prevention sheet could be detached from the regulation plate when the smoky dust prevention sheet is used in contact with the development roller in the state of being bended.
Moreover, in order to adjust the gap between the regulation plate and the development roller with the regulation plate, generally, the regulation plate is provided with a long hole and fixed onto a casing with a screw. Consequently, the smoky dust prevention sheet needs a hole in a position corresponding to the screw. This proportionally decreases the rigidity of the smoky dust prevention sheet, and thereby the smoky dust prevention sheet is more easily detached.